INS and cancer: In a five-year observation period of 10,309 DM2 patients, a significant reduction in cancer mortality was noted among those on metformin when compared to patients on sulfonylurea derivatives or insulin (3.5% vs 4.9% vs 5.8%) [6], - esophageal, liver, colorectal, pancreatic, breast and lung cancers having the greatest risk reduction [7,8].